cookie-session is a lightweight middleware for Node.js, primarily used with Express, that implements client-side session management. Unlike server-side session stores (like `express-session`), this module stores the entire session data directly within a signed, but unencrypted, cookie on the client's browser. This approach means no server-side database or resources are required for session storage, which can simplify deployments, especially in load-balanced environments. The current stable version is 2.1.1, released in April 2024, indicating active maintenance. Releases typically align with updates to its underlying `cookies` and `keygrip` dependencies, or to address compatibility with newer Node.js versions. Key differentiators include its minimal server-side footprint and the direct storage of session data in the client's cookie, making it suitable for 'light' sessions or as a complement to a secondary, database-backed store for larger data payloads.
npm install cookie-sessionVerified import paths — ran on the pinned version, not inferred.
This quickstart initializes an Express app with `cookie-session`, demonstrating how to configure the middleware, access and modify session data (`req.session`), and clear a session. It highlights crucial security considerations like providing secret keys and setting `httpOnly`, `secure`, and `sameSite` cookie options.
Update your middleware configuration to use `name: 'your_cookie_name'` instead of `key: 'your_cookie_name'`.
Remove all calls to `req.session.save()`, and update `req.session.populated` to `req.session.isPopulated`. For length, manually check `Object.keys(req.session).length`. Other removed properties have no direct replacement or were undocumented internal features.
Encrypt sensitive data before storing it in `req.session`, or use a server-side session store (`express-session`) for truly private data. Alternatively, only store non-sensitive identifiers in `cookie-session` and retrieve sensitive data from a server-side database.
To prevent replay, implement server-side validation by storing an expiration timestamp or a unique session ID in `req.session` and regularly checking its validity on the server. Always add some initial data to `req.session` (e.g., `req.session.initialized = true;`) if you want a session cookie to be set immediately.
Remove all explicit calls to `req.session.save()`. The middleware automatically handles saving changes to `req.session`.
Provide an array of strong secret strings to the `keys` option in the middleware configuration, e.g., `app.use(cookieSession({ name: 'session', keys: ['secret1', 'secret2'] }))`. In production, these should be loaded from environment variables.Ensure you add at least one property to `req.session` (e.g., `req.session.initialized = true;`) at some point during the request if you want a session cookie to be created for the user.
Use the ES Module import syntax: `import cookieSession from 'cookie-session';`. Ensure your environment supports ES Modules.